Physeal changes and range-of-motion differences in the dominant shoulders of skeletally immature baseball players

Does the presence of proximal humerus growth plate changes in young baseball pitchers happen only in symptomatic athletes? Anxray evaluation of 21 young baseball pitchers

“…Similarly to Mair et al ,10 we observed that in athletes with pain, the radiographic findings were more pronounced, although we were not able to confirm this quantitatively, because the number of patients in our sample was not large enough (fig 3). However, it was possible to observe that in athletes whose x rays had shown physeal widening, this was statistically more pronounced, even when we studied the asymptomatic athletes.…”

Sports Participation and Humeral Torsion

“…44 Humeral torsion varies with age, beginning in utero with marked bilateral humeral retrotorsion, and decreases during childhood and adolescence, so that the humerus becomes less retrotorted. 12 Greater dominant-arm retrotorsion has been demonstrated in relatively young males participating in throwing sports such as baseball 23 and European handball. 30 It has been suggested that the unilateral upper limb activity in these sports is associated with the genesis of this side-to-side difference in humeral torsion.…”

Bilateral Asymmetry of Humeral Torsion and Length in African Apes and Humans

“…Adult humeral torsion values in humans develop during growth in the proximal epiphysis (where 80% of humeral growth takes place [Pritchett, 1991]) as a result of repetitive rotational stresses, which lead to the deformation of the epiphyseal cartilage, thus resulting in reduced torsion values [Mair et al, 2004;Murachovsky et al, 2010;Thomas et al, 2012;Wyland et al, 2012]. Although the exact timing of the cessation of humeral torsion development is unknown [Cowgill, 2007], it is thought to occur at the time of epiphyseal fusion, between the ages of 16 and 20 [Krahl, 1976;Edelson, 2000].…”